1. Field of the Invention
The present invention relates to an insertion device including an elongated insertion portion to be inserted into a subject.
2. Description of the Related Art
Recently, insertion devices having an insertion portion to be inserted into a subject, for example, endoscopes, have been widely used in a medical field and an industrial field.
An endoscope used in the medical field is able to observe an organ in a body cavity by inserting an elongated insertion portion into the body cavity, which is the subject, and perform various treatments by using a treatment instrument which is inserted into an insertion channel for the treatment instrument included in the endoscope as desired.
Further, an endoscope used in the industrial field is able to perform inspections such as observation and various treatments of flaws, corrosion and the like of an area to be inspected in an object by inserting an elongated insertion portion of the endoscope into an object such as a jet engine and a factory piping.
Here, the insertion portion of the endoscope is provided with a linear member which is movable forwards and backwards in the insertion direction of the insertion portion.
To be specific, examples of the linear member provided in the insertion portion of an endoscope include a bending wire which is pulled/released to cause a bending portion provided at a distal end side in the insertion direction (hereinafter, simply referred to as a “distal end side”) of the insertion portion to be bent in multiple directions, and a coil sheath for covering the outer periphery of the bending wire.
Further, examples of the linear member include: a coil pipe wire provided in a coil pipe for making the rigidity of a flexible tube portion variable, which is located more rearward in the insertion direction (hereinafter, simply referred to as “rearward”) than a bending portion in an insertion portion, and to be pulled/released to make the rigidity of the coil pipe variable; and an operation wire to be pulled/released for a raising or lowering operation of a treatment instrument elevator in a distal end portion located more forward in the insertion direction (hereinafter, simply referred to as “forward”) than a bending portion of an insertion portion.
Further, as an example of the configuration in which the position of a linear member that moves forwards and backwards in the insertion direction is fixed in the insertion direction, Japanese Patent Application Laid-Open Publication No. 9-108176 discloses a configuration for fixing the position of the above-described coil pipe wire.
Specifically, Japanese Patent Application Laid-Open Publication No. 9-108176 discloses a fixing mechanism in which a rack formed with a plurality of grooves along an insertion direction is provided at a proximal end in the insertion direction (hereinafter, simply referred to as a “proximal end”) of a coil pipe wire, and a pinion gear of a hole portion which rotates with an operation knob engages with the rack so that when the operation knob is rotated in one direction, the engagement position of the pinion gear with respect to the plurality of grooves of the rack is shifted forward, that is, by resisting a releasing force of the coil pipe wire by utilizing the engagement between the grooves of the rack and the pinion gear in a configuration in which the rack is moved rearward to pull the coil pipe wire, the position of rack, that is, the pulling position of the coil pipe wire can be fixed, even if the hand is moved off the operation knob.
Moreover, there is a well-known configuration in which the position of a linear member is fixed by friction force by pinching a proximal end side in the insertion direction (hereinafter, simply referred to as a “proximal end side”) of a linear member between two friction members.